1. Field of the Invention
The present invention relates to a method of manufacturing a waterproof paper container for storing ammunitions and more particularly, a method of manufacturing a waterproof paper container which is a thick paper tube made of multiple paper layers by adhering an adhesive such as a hot molten adhesive on the exterior surface of the thick paper, and thereafter, coating by extruding a thermofusible synthetic resin on the surface of the adhesive.
2. Description of the Prior Art
In general, ammunition containers such as a fiber container or a fiber drum for storing ammunitions known in the art have a plurality of cases for storing the ammunitions for a long period of time and a plurality of cases for storing by heaping up in a warehouse. In as much as these conventional ammunition containers are structured with a cylindrical container simply folded in multiple with thick papers, it is real situation that great problem has been pointed out which may cause the inefficient result in detonation such as an early explosion, delayed explosion, or nonexplosion of the ammunitions owing to the deterioration of waterproof effect.
Accordingly, the present applicant developed an improvement in such ammunition container as disclosed in the U.S. Pat. No. 4,595,119 entitled "WATERPROOF PAPER CANISTER". However, since a thermofusible synthetic resin is coated integrally on the surface of the paper tube body, the paper tube and the thermofusible synthetic resin are different materials one another and a film is formed with polyethylene or polypropylene, the polyethylene or polypropylene cannot be penetrated into the paper tube and becomes impossible to maintain the strong adhesive strength.
Furthermore, since, when the thermofusible synthetic resin is coated by extruding on the external surface of the paper tube, the thermofusible synthetic resin becomes expanded at a high temperature and the paper tube is dehumidified causing the high temperature, it becomes a contracted state. Therefore, since, when the extruded and coated paper tube is cut by some voluntary size, the thermofusible synthetic resin is expanded while the paper tube is contracted in a normal temperature state, a moisture in the atmosphere becomes to penetrate into the paper tube and that the paper tube becomes expanded by the moisture.
Thus, since it is an unstable state that the adhering strength between the paper tube and the thermofusible synthetic resin is not present and they are loose from one another, the paper tube becomes expanded by the moisture in the atmosphere.
Therefore, since the magnitude of the paper tube becomes larger than that of the thermofusible synthetic layer for waterproofing, there are many disadvantages such as a bad waterproof effect.